1. Field of the Invention
The present invention generally relates to an image processing apparatus and particularly relates to an image processing apparatus that stores therein input document image data, retrieves and outputs it as needed.
2. Description of the Related Art
Typically, there is a method that, when a user checks stored data in a system of inputting and storing image data, and retrieving stored image data as needed, information such as a title, date, registrant, and file size is displayed as a list. There is another method in which data can be selected by intuition by use of a reduced image such as a thumbnail. However, when a reduced image is used, images that are apparently similar in structure can not be distinguished. As a method of addressing this problem, there is a method of extracting a specific characteristic (here, referred to a representative characteristic) when inputting image data and adding the representative characteristic as attribute information. According to the method, part of image data can be used instead of a reduced image to more specifically display contents of image. Therefore, ambiguity among images when using reduced images can be distinguished. An example of a conventional technology associated with the method is cited as follows.
In “document management system” disclosed in Japanese Patent Application Laid-open No. 2003-178071, document images can be classified in an efficient manner by extracting an area image of a figure or a photograph and using it as an attribute. When an image receiving sub-unit receives a document image, an area discriminating sub-unit performs area discriminating processing of the document image. An image cutting sub-unit classifies a figure area or a photograph area as “figure area” among a sentence area, a table area, lines, a figure area, a photograph area and the like divided by the area discriminating sub-unit and cuts a partial image of such area. A document image managing sub-unit adds the cut partial image as attribute information to management information of the document image and stores the image in a document image storing sub-unit. The image cutting sub-unit, when there exist plural figure areas or photograph areas in the input document image, can cut all of the figure areas as partial areas or cut a representative figure area or photograph area as a partial area among these figure areas or photograph areas.
However, the conventional image characteristic extracting method has the following problem. To extract and display a characteristic of image data is required in a digital multifunction product having a display unit; however, a digital multifunction product does not include a powerful computing unit such as a personal computer. Therefore, when processing is performed to discriminate area information with respect to the whole image data, the resulting heavy load may cause processing to take a long time. Even if an image processing apparatus is implemented in a digital multifunction product that has a powerful computing unit, it is desirable that the processing load is small. The whole image data may include plural figures or photographs, possibly mixed with noise, and an error occurs that an unexpected area can be extracted.